This invention pertains to pulp slurry-handling press rolls, and to slurry-handling roll presses, employing such press rolls, and in particular to a novel press roll for use in such roll presses as well as to twin roll and single roll slurry-handling presses incorporating the novel press roll.
It is already known, in the prior art, to form press rolls with liquid drainage grooves for quick and efficient removal of filtrate from the pulp mat. The following factors are affected by groove design: (a) the roll speed, as it affects the press capacity, (b) rewetting of the mat following the nip (in twin roll presses), as this determines the discharge consistency, (c) maximum roll length, and (d) roll cost. Commonly, the grooves are circumferentially formed in the roll, and a cylindrical sheath having a multiplicity of minute holes encloses the roll. Each of the grooves has a multiplicity of drilled holes formed therein for admitting filtrate therethrough for drainage into the interior of the roll. The roll comprises a cylindrical drum supported on a number of axially extended ribs which are welded to a heavy shaft. The ribs have cut outs formed therein to conduct the filtrate therethrough to flow channels, within the drum, which are defined by adjoining ribs. Such prior art press rolls are very expensive to manufacture and, functionally, they cause an unwarranted rewetting of the pulp mat.